Unreliable SCSI on TT modification

The latest tweaks and fixes to keep your machine running in tip-top shape.
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Steve
Posts: 1562
Joined: Fri Sep 15, 2017 11:49 am

Unreliable SCSI on TT modification

Post by Steve » Sun Dec 12, 2021 11:04 am

Is your TT SCSI unreliable? flaky?

Atari didn't provide term power on the TT. This is supposed to be 5v on pin 26 of the internal connection and pin 25 of the external. This is the reason we have silly internal resistors that no other SCSI computer bothers with .... makes me wonder about their logic? Anyway, it is EASY to fix... follow this guide:

TT SCSI PORT ACTIVE TERM PWR MOD.jpg
TT SCSI PORT ACTIVE TERM PWR MOD.jpg (45.87 KiB) Viewed 506 times

EXAMPLE INSTALLATION:

PXL_20211210_204003169.jpg
PXL_20211210_204003169.jpg (521.72 KiB) Viewed 506 times

You can now REMOVE all the internal resistors & use an EXTERNAL SCSI terminator on the rear port.

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